The Paris-based International Energy Agency (iea) said in its annual review of energy programs in 21 industrialized countries that Denmark was making the best effort to cut energy waste to a minimum. The verdict was the same last year, and the year before.

A country with virtually no energy resources of its own, Denmark has been forced to make the most of the energy it gets from everywhere else.

Huge reserves of oil and natural gas discovered recently in the Danish North Sea will dramatically change the country's energy picture beginning next year when the taps are turned on. By the end of the decade, 30 percent of Denmark's energy needs could be met by domestic oil and gas, and up to 70 percent by the late 1990s.

But the Danish people have been so conditioned to conserving energy -- it has become a way of life -- that further measures designed to make even better use of existing energy will be key elements in the government's new energy plan to be released this fall.

"Energy conservation, through voluntary and mandatory measures, played an essential role in our first national energy program issued five years ago," says Jan Daub, a planning expert in the Ministry of Energy, "and it will play an equally important part in the new plan."

Much of Denmark's savings in energy can be attributed to high government subsidies for home and factory insulation. Home and office heating account for nearly half of the country's total energy consumption, which fell by 16 percent in 1980 against 1979, while in the IEA area as a whole the drop was only 7 percent. A further 15 percent cut is expected this year.

Planning expert Daub says his department is still calculating the total energy in tons of oil equivalent (TOE) that recycling (formerly) waster heat -- as at the incineration facility in Copenhagen and the chemical factories in Fredericia -- saves the country each year. "I can tell you, however, that it is significant," he says.

At the Copenhagen trash-burning plant alone, recouped heat -- by heating 35, 000 apartments -- saves between 30,000 and 60,000 TOE a year, depending on the "quality" of the garbage burned.

That's not much compared to the roughly 14 million tons of oil Denmark imported last year. But it is, as Daub says, significant.

Operating 24 hours a day, the $22 million Copenhagen plant -- one of two heatrecoupment incineration facilities in the city -- burns about 12 tons of household trash an hour. Officials from Volund, the Danish company that built the plant, say that 80 percent of the heat is recouped. The leftover ashes are sold to a West German road resurfacing company.

The recycled heat from the chemical companies in Fredericia, meanwhile, will save the city about 12,000 TOE, or half its current consumption, when the project becomes fully operational next year, lopping off about $3 million from Denmark's oil-import bill.

"We've come a long way," says Jan Daub. "We still waste a lot of energy. But we've done better than most countries -- wou ldn't you agree? And we expect to do even better."